Seat System - Seating: Overview Ford Fiesta Mk6

Normal Operation

The heated seat system only operates when the engine is running. When the driver or passenger heated seat switch (located on the instrument panel) is activated, it supplies a ground signal to the Body Control Module (BCM). When the BCM receives the heated seat switch signal, it activates the appropriate (driver or passenger) heated seat relay (located in the Central Junction Box (CJB). When the heated seat relay is activated, voltage is supplied to the cushion heater mat. The cushion heater mats are directly connected to ground to complete the electrical circuit to heat the seat.

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. BCM

Scheme 1

Scheme 2

1. A1 CHECK FOR VOLTAGE TO THE DRIVER HEATED SEAT RELAY Disconnect: Driver Heated Seat Relay. Ignition ON. Measure the voltage between driver heated seat relay socket pin 1, circuit CBP17 (BN/GN), and ground. Is the voltage greater than 10 volts? Yes: Go to A2 . No: VERIFY Central Junction Box (CJB) fuse 17 (7.5A) is OK. If OK, REPAIR the circuit. If not OK, Refer to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short. TEST the system for normal operation.
2. A2 CHECK THE HEATED SEAT SWITCH GROUND CIRCUIT Ignition OFF. Disconnect: Driver Heated Seat Switch C2400. Measure the resistance between driver heated switch C2400-4, circuit GD115 (BK/GY), harness side and ground. Is the resistance less than 5 ohms? Yes: Go to A3 . No: REPAIR the circuit. TEST the system for normal operation.
3. A3 CHECK THE BCM FOR CORRECT OPERATION Disconnect all of the BCM connectors. Check for: corrosion. pushed-out pins. Connect all of the BCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new BCM . Refer to «MULTIFUNCTION ELECTRONIC MODULES»(ref-382389) . TEST the system for normal operation. No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

The heated seat system only operates when the engine is running. When the driver heated seat switch (located on the instrument panel) is activated, it supplies a ground signal to the Body Control Module (BCM). When the BCM receives the heated seat switch signal, it activates the driver heated seat relay (located in the Central Junction Box (CJB)) by grounding the relay control circuit. When the heated seat relay is activated, voltage is supplied to the driver cushion heater mat. The driver cushion heater mat is directly connected to ground to complete the electrical circuit to heat the seat.

1. DTC B1034:12 (Left Front Seat Heater Element: Circuit Short To Battery) - if the driver heated seat relay drive circuit CHS02 (YE/BU) is shorted to voltage and the BCM attempts to activate the driver heated seat relay, this DTC sets and the seat fails to heat.
2. DTC B1034:14 (Left Front Seat Heater Element: Circuit Short To Ground or Open) - if the driver heated seat relay drive circuit CHS02 (YE/BU) is open or shorted to ground and the BCM attempts to activate the driver heated seat relay, this DTC sets and the seat fails to heat (circuit open) or may be on at all times (circuit shorted to ground) until the ignition is turned OFF.
3. DTC B115B:23 (Front Driver Seat Heater: Signal Stuck Low) - sets when the BCM detects the driver heated seat switch is active during on-demand self-test or has been active for more than 2 minutes.

This pinpoint test is intended to diagnose the following

1. Heated seat relay
2. Heated seat switch
3. Wiring, terminals or connectors
4. Heater mat
5. BCM

The heated seat system only operates when the engine is running. When the passenger heated seat switch (located on the instrument panel) is activated, it supplies a ground signal to the Body Control Module (BCM). When the BCM receives the heated seat switch signal, it activates the passenger heated seat relay (located in the Central Junction Box (CJB)) by grounding the relay control circuit. When the heated seat relay is activated, voltage is supplied to the passenger cushion heater mat. The passenger cushion heater mat is directly connected to ground to complete the electrical circuit to heat the seat.

1. DTC B1036:12 (Right Front Seat Heater Element: Circuit Short To Battery) - if the passenger heated seat relay drive circuit CHS07 (GY/BU) is shorted to voltage and the BCM attempts to activate the passenger heated seat relay, this DTC sets and the seat fails to heat.
2. DTC B1036:14 (Right Front Seat Heater Element: Circuit Short To Ground or Open) - if the passenger heated seat relay drive circuit CHS07 (GY/BU) is open or shorted to ground and the BCM attempts to activate the passenger heated seat relay, this DTC sets and the seat fails to heat (circuit open) or may be on at all times (circuit shorted to ground) until the ignition is turned OFF.
3. DTC B115A:23 (Front Passenger Seat Heater: Signal Stuck Low) - sets when the BCM detects the passenger heated seat switch is active during on-demand self-test or has been active for more than 2 minutes.

This pinpoint test is intended to diagnose the following

1. Heated seat relay
2. Heated seat switch
3. Wiring, terminals or connectors
4. Heater mat
5. BCM

The heated seat system only operates when the engine is running. When the driver or passenger heated seat switch (located on the instrument panel) is activated, it supplies a ground signal to the Body Control Module (BCM). When the BCM receives the heated seat switch signal, it activates the appropriate (driver or passenger) heated seat relay (located in the Central Junction Box (CJB)). When the heated seat relay is activated, voltage is supplied to the cushion heater mat. The cushion heater mats are directly connected to ground to complete the electrical circuit to heat the seat.

1. DTC B1034:14 (Left Front Seat Heater Element: Circuit Short To Ground or Open) - if the driver heated seat relay drive circuit CHS02 (YE/BU) is open or shorted to ground and the BCM attempts to activate the driver heated seat relay, this DTC sets and the seat fails to heat (circuit open) or may be on at all times (circuit shorted to ground) until the ignition is turned OFF.
2. DTC B1036:14 (Right Front Seat Heater Element: Circuit Short To Ground or Open) - if the passenger heated seat relay drive circuit CHS07 (GY/BU) is open or shorted to ground and the BCM attempts to activate the passenger heated seat relay, this DTC sets and the seat fails to heat (circuit open) or may be on at all times (circuit shorted to ground) until the ignition is turned OFF.

This pinpoint test is intended to diagnose the following

1. Heated seat relay
2. Wiring, terminals or connectors
3. BCM